holier-than-thou vs self-righteous

holier-than-thou and self-righteous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
holier-than-thou	No	Yes	No	No
self-righteous	No	Yes	No	No

As adjectives, holier-than-thou and self-righteous are synonyms defined as:

holier-than-thou and self-righteous: excessively or hypocritically pious

Other synonyms of holier-than-thou include pharisaic, pharisaical, pietistic, pietistical, sanctimonious.

holier-than-thou (adjective)	self-righteous (adjective)
excessively or hypocritically pious	excessively or hypocritically pious